I am sure pinching would help. My problem is having too many of them to give them much attention - at least 50 feet of row. After hard winters like last winter they were all cut to the ground, but in normal or mild winters they tend to retain life in their stems almost to the former year's top growth. With any microphylla/greggii you get an early bloom if live branches survive, a nice thing, but bad for quick pruning, messy later when the current year's shoots of grown.